(1) Field of the Invention
The present invention is generally related to motorcycles, and in particular to front wheel suspension and steering systems for motorcycles.
(2) Description of the Related Art including information disclosed under 37 CFR 1.97 and 1.98
A front suspension and steering system in a motorcycle must be designed to bear a portion of the weight load of the motorcycle and to also absorb road shocks caused by irregularities in the road. This design objective of the suspension system is usually accomplished through a combination of springs and fluid-based dampers contained in the telescoping front fork tubes of a traditional motorcycle.
Another major design objective of the front suspension and steering system is to transmit steering torque from the rider to the front wheel, while at the same time providing straight-line tracking stability and also biasing the return of the front wheel from a turned position to a straight-line position during operation. These objectives are normally met through the selective application of rake angle, trail, and other design elements of traditional front fork assemblies.
It has been recognized that the suspension function and the steering function are in concept independent of one another and thus should ideally be separated from one another structurally, in part because the weight, size and design of the load-bearing components of the system are different that those necessary for the components of the steering system. Yet in most motorcycle designs these functions are combined in the structure of the suspension and steering system and thus they affect one another. For example, it would be desirable to transmit roads shocks from the front wheel to the body of the motorcycle, where the engine and thus the center of mass of the motorcycle are located, along the shortest and most direct path possible. Yet in the traditional motorcycle design all weight loads and road shocks are transmitted through the front fork tubes to the steering head, resulting in a steering head assembly that is heavier than necessary to support the steering function alone; and also resulting in all weight and shock loads being transmitted between the front wheel and the body of the motorcycle along an indirect and thus unnecessarily long path that includes the steering head.
Further, in the traditional design the application of steering torque to the front fork tubes affects the friction between the telescoping fork tubes and thus affects the response of the suspension system to road shocks. Also, because the traditional fork tubes are extended at a rake angle, weight and shock loads affect the friction in the telescoping tubes and thus their performance. As a consequence road shocks and weight loads affect the steering of the motorcycle; and, conversely, the application of steering torque affects the response of the suspension system to road shocks.
Accordingly, it is the object and purpose of the present invention to provide an improved suspension and steering system for the front wheel of a motorcycle.
More specifically, it is an object and purpose of the present invention to provide a suspension and steering system in which the suspension and steering functions are improved by being substantially separated from one another structurally.
It is also another object and purpose of the present invention to provide a suspension and steering system in which weight and shock loads are transmitted between the front wheel and the body of the motorcycle through structural components, including spring and damper elements, that are separate from the steering column of the motorcycle.
These and other objects and purposes are more fully set forth and will be evident from the drawings and detailed description of the invention set forth below.